Dental crown elevation

ABSTRACT

Apparatus for removing tooth crowns (or caps or inlays) comprises a source of fluid pressure, including ducting; and, means to couple the ducting in pressure transmitting relation with the tooth side of the crown for effecting separation of the crown from the tooth in response to fluid pressure transmission to that side of the crown.

United States Patent Ballard [54] DENTAL CROWN ELEVATION [72] inventor: Louis M. Ballard, 1911 Wilson Avenue,

Arcadia, Calif. 91006 [22] Filed: June 9, 1970 211 Appl. No.: 44,810

[52] U.S. Cl. ..32/43 [51] int. Cl ..A61c 3/16 [58] Field oiSeareh ..32/6l, 43, 60

[56] References Cited UNITED STATES PATENTS 3,521,356 7/1970 Newman "32/60 [45] Apr. 4, 1972 3,135,144 6/1964 Cameron ..8l/3.1

Primary Examiner-Robert Peshock Attorney-White, Haefliger and Bachand [57] ABSTRACT Apparatus for removing tooth crowns (or caps or inlays) comprises a source of fluid pressure, including ducting; and, means to couple the ducting in pressure transmitting relation with the tooth side of the crown for effecting separation of the crown from the tooth in response to fluid pressure transmission to that side of the crown.

3 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION This invention relates generally to dental equipment, and more particularly concerns method and apparatus for removing crowns, caps and inlays from teeth.

Dental crowns, caps and inlays are commonly affixed to teeth by cementing them in place. Due to the rigidity of the cement bond, it is oftentimes extremely difficult and/or painful to remove them, as for example by prying or other mechanical leverage exerting activity.

SUMMARY OF THE INVENTION It is a major object of the invention to provide apparatus and method for removing dental crowns, caps and inlays through application of fluid pressure, and thereby to eliminate the problems associated with conventional mechanical removal of same.

Basically, and in its apparatus aspects, the invention is embodied in apparatus comprising a source of fluid pressure including ducting, together with means to couple the ducting in fluid pressure transmitting relation with the inner or tooth side of the crown for effecting separation of the crown from the tooth in response to fluid pressure transmission to that inner side of the crown. In this regard, the term crown will be used in a broad sense as inclusive of caps and inlays.

As will appear, the means for coupling the ducting to the crown may typically include an externally threaded tubular fitting attachable to the crown at a bore therein and through which hydraulic pressure is transmissible, that fitting for example comprising a self-tapping screw; also the coupling means may include structure sealing off between the fitting and the crown at the side thereof opposite the tooth, as will appear. Additionally the coupling means may include a drive to effect rotation of the threaded fitting in the crown bore, and

- in tapping relation therewith.

The referred to source of fluid pressure may typically include a hydraulic cylinder communicating with the ducting, a plunger movable in the cylinder, and plunger activating mechanism including a manual control. In this regard, the cylinder may define a barrel of a gun having a manual control trigger. The source of fluid pressure may also include a disposable cartridge containing the hydraulic fluid and communicable with the cylinder.

In its method aspects, the invention basically includes the steps of providing a source of fluid, and communicating the latter to the tooth or inner side of the crown bonded to the tooth and with sufficient fluid pressure that the bond separates. The communicating step may typically include forming an opening through the crown to pass the fluid, the forming for example including the step of tapping a thread in the crown to receive a threaded tubular fitting as referred to, to pass the pressurized fluid.

These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which:

DRAWING DESCRIPTION FIG. 1 is a side elevation of one form of apparatus embodying the invention;

FIG. 2 is an enlarged view, partly in section, showing the attachment of the coupling means to the crown; and

FIG. 3 is an illustration, in three sub-views, of the steps involved in elevating a crown relative to a tooth to which it was attached.

DETAILED DESCRIPTION In the drawings, a tooth is schematically shown at as having a crown 11 attached to the tooth, as for example by cementing or bonding at 12 of the crown skirt 11a to the outer wall of the tooth. While a crown in the form of a cap is shown,

other forms of crowns such as inlays are also contemglated.

In accordance with the invention, a source of flui pressure including ducting is provided, and in this regard the ducting may include a flexible tube 13 in operative communication with fluid such as sterilized petroleum jetty in a disposable cartridge 14.

Also in accordance with the invention, means is provided to couple the ducting in fluid transmitting relation with the tooth side of the crown for effecting separation of the latter from the tooth in response to fluid pressure transmission to that side of the crown. Such means may typically include an externally threaded tubular fitting as for example appears at 16 in FIG. 2, the fitting being attachable to the crown wall 1 lb at a threaded bore 17 formed therein, and through the bore 17 of which the fluid pressure is transmissible. FIG. 2 shows the fitting bore 18 in communication with the space 19 beneath the crown wall 11b, for supplying fluid under pressure sufficient to displace the crown upwardly and thereby enable separation of the crown from the tooth. In this regard, the crown may be hydraulically elevated, as is shown in FIG. 3(0), with pressurized fluid at 20 urging the crown top llb upwardly.

The means to couple the ducting in fluid transmitting relation with the crown may advantageously include structure sealing off between the fitting and crown, as for example the elastomer seal ring 21. The latter becomes compressed against the crown wall or top 11(b), about the fitting 16, in response to tightening of the fitting into the threaded bore 17. For this purpose, a flange or shoulder 22 or the fitting may exert squeezing force on the seal ring.

Rotation of the threaded fitting 16 in the crown bore 17 in the self-tapping relation may be efiected by means of a head 23 coupled to the shaft 16a of the tubular fitting. The head 23 may have wrench engageable flats to be turned by a wrench. Alternatively, the numeral 23 may represent a manually rotatable knob, for rotating the fitting 16. FIG. 3(a) indicates use of a small drill 26 for initially forming the bore in the top wall 11b of the crown, to be later tapped by the fitting l6 during completion of the connection as seen in FIG. 3(b).

FIG. 2 shows the fitting shank 16a as communicating with the tubing 13 via a bore 28 in a ducting housing 29, an annular groove 30 in the rotary shank, and ports 31 extending between that groove and the bore 18 in the shank.

Finally, FIG. 1 shows the manual control unit for the source of fluid pressure as defining a gun wherein the gun barrel defines an hydraulic cylinder 33 to which hydraulic fluid is communicable from disposable cartridge 14 via porting 34. This is effected by thumb pressure on a plunger 35 extending into the cylinder to urge fluid therefrom and into porting 34. A threaded fitting 36 retains the cylinder in position, as shown.

A plunger 37 is movable in cylinder 33, under the control of a manually operable trigger 38 to urge hydraulic fluid into the tubing 13, when desired, to elevate the crown. Trigger 38 is pivotally mounted at 39, and pivotally connected at 40 to the plunger 37. A handle 41 supports the mechanism, as shown.

I claim:

1. The method of removing a tooth crown that includes,

a. providing a source of fluid pressure, and

b. communicating said fluid pressure to the tooth side of a crown bonded to a tooth and entrapping and building up said pressure to separate the crown from the tooth.

2. The method of claim 1 wherein said communicating step includes forming an opening through the crown to pass said fluid.

3. The method of claim 2 wherein said forming step includes tapping a threaded opening in the crown to receive a threaded tubular fitting to pass said fluid.

I I l 

1. The method of removing a tooth crown that includes, a. providing a source of fluid pressure, and b. communicating said fluid pressure to the tooth side of a crown bonded to a tooth and entrapping and building up said pressure to separate the crown from the tooth.
 2. The method of claim 1 wherein said communicating step includes forming an opening throUgh the crown to pass said fluid.
 3. The method of claim 2 wherein said forming step includes tapping a threaded opening in the crown to receive a threaded tubular fitting to pass said fluid. 